1. Field of the Invention
The present invention relates to building construction and pertains particularly to a forming system and method for forming architectural concrete walls.
2. Description of the Related Art
Several methods and systems for constructing walls exist in the building industry. Each of the different wall systems has its own advantage for particular applications. Most modern high-rise buildings utilize a steel-girder frame with curtain wall covering. The underlying frame-work comprises welded steel girders. The covering is typically glass, stone or concrete panels secured to the girder construction.
Most low-rise buildings of no more than three stories employ a wood-frame with wood, stucco or other covering. The underlying framework is typically wooden beam and post construction. The covering of the building can be wood, stucco or some other suitable material.
Another type of construction employs concrete re-bar. In this type of construction, concrete is poured into forms and strengthened by reinforcing bars to form walls which also support the building. Columns for structural support and walls are formed around re-enforcing bars by means of concrete forms. The walls are poured in sections typically 10-14 feet in height. In its preferred form, the surface of the concrete walls provide the finished surface of the structure. This is known as architectural concrete construction.
One problem with architectural concrete construction is the difficulty and high cost associated with obtaining a satisfactory finished appearance. Present known techniques have difficulty in minimizing flaws that include, but are not limited to: 1) closely spaced tie holes, 2) water loss or leakage which results in discoloration, abrasion and sanding at the tie holes, 3) discoloration associated with form release agents, and 4) air pockets due to form release agents and leakage at formed panel joints.
Architectural concrete construction is desirable because it provides significant functional advantages for certain types of structures. Such advantages include utilizing the structural component of the building as the architectural finish skin, and eliminating the cost and complexity of additional systems, such as coverings and the like. A high quality architectural concrete can provide a highly durable, long lasting substantially zero maintenance system. It can also provide a pleasing appearance for a long period of time.
One example of world-renown architectural concrete construction is The Salk Institute in La Jolla, Calif. This building complex is often referred to as the standard for architectural concrete construction. Achieving even this standard is difficult with existing technology.
In the prior approach to forming architectural concrete walls, forms were typically made of sheets or panels of plywood attached to a framework of aluminum and/or wooden beams. The face of the plywood panels formed the surface texture of the concrete wall. Referring to FIG. 1, an exemplary wall section of the existing Salk Institute building structure designated generally by the numeral 10 is illustrated. In construction, the opposing faces of the forms were tied together by means of tie rods or snapties comprising bolts or rods extending through holes between the opposing form sections. These ties usually extended through the concrete and penetrated the form face. A sufficient number of tie rods or snapties were used to insure that the panels would be held in the proper spatial relationship and be prevented from bowing or buckling. As illustrated in FIG. 1, up to 12 or 14 tie rods were used for each panel of about 4.times.10 or 12 ft forming the wall sections 14. The tie rods were removed and holes left in the wall were covered and sealed by lead discs 16.
In the original construction, facing edges of the plywood sheets were beveled to provide a triangle or V-shaped ridge 18 between wall panels 14 formed by each sheet member of a form panel section. This added to the pleasing appearance of the overall structure.
One significant disadvantage with this prior art construction was that chemical release agents used to inhibit concrete from sticking to the form panels contributed to discoloration of the wall structure. Such release agents also frequently resulted in air pockets which further impacted the final appearance of the wall. These disadvantages in addition to the necessity of employing closely spaced tie holes, added to the maintenance problem of the wall structure. The tie holes were sealed by means of lead discs.
The present architectural concrete forming system and methods were developed in order to improve upon the Salk Institute standard.
It is desirable that improved form systems and wall forming methods exist to provide a higher quality, lower maintenance architectural concrete wall surface.